Magnetic electrical switch



Nov. 13, 1956 A. 1.. KELLETT 2,770,697

MAGNETIC ELECTRICAL SWITCH Filed April 1, 1954 2 Sheets-Sheet l INVENTOR. Amen Z, KHAN;

BY 16W 1956 A. L. KELLETT MAGNETIC ELECTRICAL SWITCH 2 Sheets-Sheet 2 Filed April 1; 1954 IN VEN TOR. A M/m2 Z. K5445 United States Patent 2,770,697 MAGNETIC ELECTRICAL SWITCH Alfred L. Kellett, New Hyde Park, N. Y. Application April 1, 1954, Serial No. 420,400

Claims. (Cl. 200-87) The present invention relates to electrical switches of the sealed, magnetically actuated type and, more particularly, to such a switch which is an improvement over the switch disclosed in my copending application for Letters Patent of the United States, Serial"No 346,569, filed April 3, 1953, now abandoned.

An object of the present'invention is to provide a moisture-proof switch of the foregoing type which is simple and economical in construction and positive and reliable in operation.

Another object is to provide such a switch which is adapted for utilizing a strong magnet of a small size and a compact construction.

Another object is to provide such a switch wherein the switch elements'are arranged for wiping contact to minimize arcing.

A further object is to provide such a switch which moves rapidly from one position to another.

Other and further objects will be obvious upon an understanding of the illustrative embodiment about to be described, or will be indicated in the appended claims, and various advantages not referred to herein will occur to one skilled in the art upon employment of the invention in practice.

A preferred embodiment of the invention has been chosen for purposes of illustration and description and is shown in the accompanying drawing, forming a part of the specification, wherein:

Fig. l is a perspective view illustrating the exterior of a switch in accordance with the present invention.

Fig. 2 is a sectional view taken substantially along the line 22 on Fig. 1.

Fig. 3 is a sectional View taken substantially along the line 33 on Fig. 1.

Fig. 4 is a sectional view taken along the line 4--4 on Fig. 3.

Fig. 5 is a view similar to Fig. 4 illustrating another arrangement for mounting the switch contact operating element.

Fig. 6 is an enlarged fragmentary sectional view taken along the line 6-6 on Fig. 5.

Fig. 7 is a plan view of the switch illustrating toggle mechanism for effecting rapid operation of the switch.

Fig. 8 is a side view of the mechanism shown in Fig. 7.

Referring to the drawings in detail and, more particularly to Figs. 1 to 4 thereof, there is shown a switch generally comprising a base or mounting plate 10, a box 11 secured to the mounting plate in a manner to provide an airtight and moisture-proof closed container for housing the switching elements as about to be described, and a casing 12 secured to the front wall 14 of the box 11 for housing switch operating means.

The switching elements include a terminal block 15, a pair of adjacently spaced apart switch elements 16 secured to the terminal block, each element having a conductor 17 electrically connected thereto which conductor leaves the container through a sealed opening, and each element being provided with an inclined or ICC slightly curved section 19 adapted for wiping engagement by a bar 20 for establishing an electrical connection therewith, a plate-like member or strip 21 formed of magnetic material and bent along its length, insulating means 22 connecting the bar 20 to one end of the member 21, and means for pivotally mounting the member 21 for rocking movement at the interior of the wall 14 in a manner whereby the bar is adapted to be moved into and out of wiping engagement with the switch element sections 19.

i In Figs. 2 to 4, these pivotal mounting means are illustrated as comprising a pair of spaced ears 24 formed integral with the box Wall 14 and having aligned, apertures 25 for rocking movement therein ofextensions 26 provided at about the middle of each side of the member 21. In Figs. 5 and 6, these means are illustrated as comprising a boss or stud 27 formed on the interior. of the box wall, a central slot 28 in the member 21 for receiving the boss to mount the same thereon for rocking movement, and a head or enlargement 29 on the free end of the boss for retaining the member 21 in operatiye connection therewith. Either of these means facilitates mounting the member 21 in a rapid and inexpensive manner.

The switch operating means include a horse shoe or U shaped magnet 30 in the casing 12, having its poles facing the exterior of the box wall 14 adjacent the magneticmember 21 and a handle 31 secured to the magnetv intermediate its poles and extending through a slot 32 in the casing 12, which slot is aligned with the member 21, whereby the magnet 30 is adapted to he slid back and forth to alternately attract the ends of the member 21 and effect rocking movement thereof.

Preferably, the magnet is of the Alnico type and is very powerful for its size, whereby rapid movement of the member 21 is effected to minimize arcing between the elements 16 and the bar 20. In order to more eifectively utilize the magnet the poles thereof may be slidably disposed in the recesses 35 formed on the exterior of the wall 14, whereby the magnet is brought closer to the member 21 and therefore its magnetic field must only pass through a wall section of reduced thickness. There recesses also greatly facilitate mounting the magnet for sliding movement by serving as guide slots for the poles thereof.

While the member 21 is shown herein as being arcuately bent along its length, it will be understood that it could have two straight sections disposed at an angle equivalent to the curvature shown.

In Figs. 7 and 8, a toggle mechanism is shown for effecting rapid movement of the magnet 30 from one position to another. This mechanism comprises an L shaped bracket 39 secured to the casing 12, a pair of spaced U shaped guide members 43 on the bracket providing a guide slot therebetween, a rod 42 having one end connected to the magnet handle 31 and having at its other end a protuberance 43 for a purpose that will be described hereinafter, a generally U shaped operating member 44 having a pair of parallel, spaced apart arms 45 each formed with a guide slot 46 for receiving a guide pin 47 mounted on the bracket and having a manually engageable handle arm 49 similarly slotted and guided, and a coiled spring 50 passing under the guide members 41 with its ends secured to the arms 45 at their free ends and being connected at the midpoint thereof to the protuberance 43 of rod 42.

When the operating member 44 is slid from one position to another, such movement tends to reverse the position or curvature of the spring 50, whereupon the spring is loaded and suddenly moves the magnet sliding rod 42 upon such reversal.

It will be appreciated that the mounting plate 10, the

Patented Nov- 13, 1956- box 11, and the casing 12, as Well as other elements of theswitch which so permit, are constructed of electrically non-conductive plastic material which facilitates manufacture and assembly of the switch parts constructed therefrom. For example, the container can be sealed so securely that the atmosphere can be inerted by a noncombustion supporting gas to minimize oxidation of the switch element 16 and the bar 20.

From the foregoing description, it will be seen that the present invention provides a novel and improved magnetically operated switch wherein the switching elements are completely sealed in a closed container to prevent corrosion of switch parts and the safe use of switch in locations where explosive vapors are likely to exist, for example, in coal mines and the like.

As various changes may be made in the form, construction and arrangement of the parts herein, without departing from the spirit and scope of the invention and without sacrificing any of its advantages, it is to be understood that all matters are to be interpreted as illustrative and not in any limiting sense.

What I claim is:

1. A switch comprising a sealed container, switch elements in said container, each of said switch elements having an inclined section, a member formed of magnetic material and bent along the length thereof, means adjacent a wall of said container pivotally mounting said member for rocking movement within said container, means including a conductive bar insulatedly carried by one end of said member adapted to move into and out of wiping engagement with said switch elements upon rocking of said member, a magnet adjacent the exterior of the aforementioned container Wall, and means for slidrespect to said member to alternately attract the respective ends of said member and effect rocking movement thereof.

2. A switch according to claim 1, wherein said magnet mounting means include a pair of recesses formed in said container wall and extending lengthwise with respect to said member, and said magnet is a horse shoe magnet having its poles slidably disposed in such recesses.

3. A switch according to claim 1, wherein said member is an arcuate plate having a central slot, and said pivotal mounting means include a boss on the interior of said container wall extending through said slot and having an enlargement for retaining said member thereon.

4. A switch according to claiml, including a casing for said magnet, and manually engageable means for effecting movement of said magnet.

5. A switch according to claim 4, including a toggle connection between said magnet and said manually engageable means for effecting rapid movement of said magnet from one. position to another.

References Cited in the file of this patent UNITED STATES PATENTS 1,529,470 Dowd Mar. 10, 1925 2,231,158 Davis Feb. 11, 1941 FOREIGN PATENTS 548,466 Great Britain Oct. 12, 1942 559,453 Great Britain Feb. 21, 1944 613,270 Great Britain Nov. 24, 1948 1,013,025 France Apr. 23, 1952 

